SEL-300G

Generator Relay

The SEL-300G is a comprehensive, multifunction relay designed for primary and/or backup protection of synchronous machines of any size. It provides globally proven reliability for the stable operation and control of small, medium, and large generators. By integrating protection, monitoring, control, and communication functions into a single device, it reduces the complexity of generator protection systems while maximizing efficiency.

Key Features

Comprehensive Winding Protection

100% Stator Ground Protection: Protects the entire stator winding by combining fundamental frequency and third-harmonic voltage elements.
Differential Protection: Quickly detects internal faults through phase or ground differential protection elements.
Abnormal Operating Condition Detection

Power Protection: Prevents prime mover damage via reverse power and low forward power detection.
Overexcitation Protection (24, Volts/Hz): Prevents transformer and generator core heating caused by magnetic flux oversaturation.
Loss-of-Field Protection (40): Detects excitation system failures to prevent loss of synchronism.
Negative-Sequence Overcurrent Protection (46): Protects the rotor from overheating caused by unbalanced loads.
System Protection

Frequency and Voltage Protection: Offers six levels of over- or underfrequency protection with time accumulators, plus over/undervoltage elements.
Out-of-Step Protection (78): Detects loss of synchronism using single or dual blinder schemes.
Expansion Capabilities

Field Ground Protection: Works with the SEL-2664 Field Ground Module for precise rotor insulation monitoring.
Temperature Monitoring: Supports real-time monitoring of up to 12 machine temperatures through SEL-2600 Series RTD Modules.

High-Accuracy Metering

Provides precise measurement of voltage, current, power, power factor, and energy, minimizing the need for external meters.
Event Analysis and Recording

Event Reports and SER: Facilitates detailed root-cause analysis through high-resolution oscillographic event reports and Sequential Events Recorder (SER) functions.
Unsolicited Fast SER: Rapidly transmits fault data to supervisory systems for immediate response.
Asset Condition Monitoring

Optimizes maintenance schedules via breaker contact wear monitoring and station battery voltage monitoring.
SELogic Control Equations

Offers user-definable control logic for customizing advanced protection and automation sequences.

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